As a participating member of the Primary Breast Cancer Therapy Group (NSABP) the University of Maryland and affiliated hospitals will contribute to on-going and future proposed protocols, and conduct the care and follow up of patients entered in such protocols, and to obtain necessary tissues for biological markers. The current proposal seeks funding to continue funded participation in the NSABP to: (a) continue patient accrual at a more intense role; (b) maintain follow up on these patients already entered into NSABP protocols; and (c) collect appropriate and necessary biological material. The University of Maryland currently participates in the following protocols: (1) B-06, which is a trial to compare the worth of segmental mastectomy with and without breast radiation with total mastectomy plus axillary dissection. All patients shall undergo axillary dissection and those with histologically positive lymph nodes will recieve adjuvant chemotherapy alone. (2) B-09, is a trial to determine whether the anti-estrogen, Tamoxifen, when combined with chemotherapy, improves the results obtained with adjuvant chemotherapy alone. (3) B-07 and B-08 are closed to patient entry. The principal investigator is the chairman of the Stage III breast cancer committee of the NSABP, which is developing a new protocol design for such license.